Process for the hydrocracking of hydrocarbons in two stages to produce gasoline with a reduced consumption of hydrogen



United States Patent 3,360,456 PROCESS FOR THE HYDROCRACKING 0F I-IY-DROCARBONS IN TWO STAGES T0 PRODUCE GASOLINE WITH A REDUCED CONSUMPTIONOF HYDROGEN Joseph K. Kosiba, Port Arthur, and Theodore Rice, Beaumont,Tex., assignors to Gulf Research & Development Company, Pittsburgh, Pa.,a corporation of Delaware No Drawing. Filed Oct. 14, 1965, Ser. No.496,166 3 Claims. (Cl. 20859) Our invention relates to a two-stagehydrocracking process for the production of lower boiling materials,such as gasoline, with a reduced consumption of hydrogen.

It has been suggested previously in the art that conversion of higherboiling hydrocarbon materials, such as furnace oils and gas oils, intolower boiling materials, such as gasoline, could be achieved byhydrocracking processes. These suggested procedures generally involvecontacting higher boiling hydrocarbon with hydrogen at hydrocrackingtemperatures and pressures in the presence of a dual componenthydrocracking catalyst, i.e., wherein one component has hydrogenationactivity and the other component has hydrocracking activity. Catalystsof this type are well-known in the art and can comprise, for example,Group VI and VIII metals supported on refractory metal oxides. Thesecatalysts are known to crack randomly both alkyl and aryl hydrocarbonmaterials thereby effecting a general reduction in the boiling range ofconverted material. It has also been suggested in the art that certaineconomies might be effected in utilities required for the conduct ofsuch processes if the operation were conducted in two stages. The theoryupon which such two-stage operations are predicated would appear to bethat the more easily convertible materials could be hydrocracked in afirst stage operating at a low temperature and such converted materialre moved therefrom, while the more difficulty convertible componentscould be hydrocracked in a second stage employing a substantially highertemperature. The purported advantage to be gained from a two-stageprocess of this type is that a certain portion of the conversion can beattained at a sufficiently low temperature that a savings in over-allheating requirement of the process is realized.

'While such previously suggested hydrocracking processes have beeneffective in the production of lower boiling components in good yields,such procedures, both single stage and multistage, heretofore have beencharacterized consistently by high hydrogen consumption. Although thisrelatively high hydrogen consumption can be tolerfrom about 750 to 1000F., a pressure in the range from about 250 to 750 p.s.i.g., a liquidhourly space velocity (LHSV) in the range from about 0.5 to 4.0 volumesof hydrocarbon charge stock per hour per volume of catalyst with ahydrogen consumption of less than 200 standard cubic feet of hydrogenper barrel of hydrocarbon charge stock while in the presence of ahydrogenation catalyst composited with an activated alumina having lessthan about percent of its pore volume in pores larger than 70 A radius.In this first stage the operating conditions employed are selected fromthe ranges set forth above so as to provide a conversion from about 30to 60 percent by volume to materials boiling below the initial boilingpoint of the charge stock. From the efiluent of this first stage areseparated a first gasoline fraction boiling up to about 400 F. and afraction boiling above 400 F. The fraction boiling above 400 F.

is then passed to a second stage where such fraction is hydrocrackedunder more conventional conditions. In this second stage the 400 F.+fraction is contacted with hydrogen at a temperature in the range from600 to 800 F., a pressure in the range from 1000 to 3000 p.s.i.g., aLHSV from 0.5 to 2.0 and a hydrogen consumption of at least 1000standard cubic feet per barrel of 400 F.+ fraction while in the presenceof a dual component hydrocracking catalyst. The particular operatingconditions employed in this second stage are selected from the aboveranges so as to effect a conversion of at least 70 percent by volume tomaterials boiling below 400 F. A second gasoline fraction boiling up to400 F. is then separated 4 from the second stage effluent. The first andsecond gasoated in refineries where an abundance of hydrogen is Havailable at low cost from other refinery processes, such as forexample, naphtha reforming, such previously suggested hydrocrackingprocedures are less desirable from an economic view point in a refinerywhere surplus hydrogen is scarce and operation of the previouslysuggested processes would require an auxiliary hydrogen manufacturingplant.

Our invention relates to a novel two-stage hydrocracking process whereinthe hydrogen consumption is substantially lower than that obtained withthe conventional one-stage hydrocracking process previously suggested bythe art and the gasoline octane number is significantly higher than isproduced by the previously suggested process. The process of ourinvention comprises hydrocrack ing in a first stage a hydrocarbon stockboiling in the range from about 400 to 850 F. and containing less thanabout 5 ppm. nitrogen under substantially dehydrogenative conditions.This hydrocracking in the first stage is accomplished by contacting thehydrocarbon charge stock with hydrogen at a temperature in the rangeline fractions can then be blended so as to provide a total gasolineproduct.

Suitable charge stocks to the first stage of our process include anypetroleum hydrocarbons boiling generally in the range from 400 to 850 F.and containing less than 5 ppm. nitrogen such as, for example, straightrun light furnace oils, full range straight run furnace oils and gasoils. The stocks charged to the first stage of our process can also bearomatic stocks, i.e., containing as much as to percent aromatichydrocarbons. Advantageously, the hydrocarbon charged to the first stagecan also comprise a large proportion, above about 30 or 40 percent byvolume, of hydrocarbon components containing at least one saturatedring.

The support for the catalyst employed in the first stage i of ourprocess must be an activated alumina which has has been depositedthereon. These alumina supports are also generally characterized by asurface area greater than square meters per gram, a sodium content ofless than 0.05 percent and less than about 0.05 percent sulfur in theform of sulfates. Aluminas of the type required in the first stage ofour process are available commercially, such as for example, H-44alumina manufactured by the Aluminum Company of America. Alternatively,these aluminas can be prepared from appropriate starting materials inany convenient way. These aluminas can be prepared, for example, inaccordance with procedures described in US. Patents Numbers 3,151,939,3,151,940 and 3,188,174. Briefly, in accordance with the methodsdisclosed in the above-mentioned patents, alumina carriers or supportsuseful in the present invention can be prepared by drying and calcininga material predominantly composed of aluminum hydroxide containing from1.2 to 2.6 moles of water of hydration. A wide variety of aluminum saltsare suitable for preparation of .this specific aluminumhydroxide, suchas, for example,

' or lower water of hydration contents than the 1.2 to 2.6

moles per mole of A1 For the same reason care should be exercised duringneutralization so as to avoid a localized higher or lower pH value. Thealuminum hydroxide for-med as described is separated from the aqueousmixture, washed to remove any undesirable salts and is then dried toremove entrained or mechanically held water before a stable product isobtained. Drying can be eifected at an elevated temperature above about170 F. To avoid undesirable transformation of the aluminum hydroxideinto a form having a higher or lower water of hydration content suchdrying temperatures can be maintained throughout the above-mentionedprecipitation and washing steps until the drying is completed.Alternatively, the transformation of the precipitated aluminum hydroxideinto less desirable forms can be avoided by effecting both precipitationand drying with promptness. Ordinarily the precipitation and dryingshould be accomplished within a period of at most 24 hours andpreferably within 4 to 8 hours or less when this expedient is employed.According to another technique the undesirable transformation can beretarded or avoided by conducting the precipitation in the presence ofan acetate ion or by employing a bufiered precipitating solution. Afterdrying to remove the entrained, adherent or mechanically held water, thealuminum hydroxide is calcined to remove water of hydration and theactivated alumina obtained thereby is I useful as a carrier for thehydrogenation catalyst of the first stage of our process.

The activated alumina carrier having the pore size distribution requiredin our invention is composited with a hydrogenating component of thekind customarily employed in a hydrocracking catalyst such as Group VIand VIII metals, the oxides or sulfides thereof, such as, for example,nickel, cobalt, platinum, palladium, molybdenum,-nickel sulfide andtungsten sulfide. Any conventional procedures for compositing porouscarriers to form a multi-component catalyst can be used to prepare thecatalyst required by our invention. Ordinarily we prefer to impregnatethe activated alumina with an aqueous solutionof a salt of thehydrogenating metal followed by drying and calcining. If twohydrogenating components are to be employed, such as a nickel-tungstenmixture, it

is advantageous to deposit first one of the components, such astungsten, followed by drying and calcining and then impregnate with anaqueous solution of a salt of the other metal, such as nickel, followedby a second drying and calcining. Other known procedures such assimultaneous impregnation of both metal components can s also beemployed. See for instance US. Patent 2,703,789,

of. McKinley and Pardee. Between about 0.5 and 35 percent by weight ofhydrogenating component may be incorporated into the alumina support. Inthe case of a nickeltungsten catalyst, between about 3 and 25 percent byweight of tungsten and between about 0.5 and 10 percent by weight ofnickel can be employed. Although We may refer to the metal components assulfides or in sulfided form this is not to be taken as an indicationthat they are necessarily present as conventional sulfides since thesulfur component may be present in other combinations such as, forexample, nickel thio-tungstate. This catalyst composite can also bepromoted with a halogen, such as fluorine, present in an amount fromabout 0.5 to about 5 percent by weight based upon the total catalystcomposite. The presence of from about 1 to about 15 percent silica canalso be employed to promote the catalyst employed in the first stagev ofour process.

The importance of employing in the first stage of our process a catalystsupported on a carrier having the abovedescribed pore size distributioncan be demonstrated by hydrocracking a highly aromatic, refractory,fluid catalytically cracked furnace oil distillate which is suitable foruse as a feed stock herein using catalysts prepared from aluminas havinga variety of pore size distributions. Thus, employing (1) an activatedalumina prepared by drying and calcining an aluminum hydroxidecontaining from 1.2 to 2.6 moles of water of hydration, (2) a commercialactivated alumina, (3) a commercial activated eta alumina and (4) acommercial activated alumina be lieved to be a gamma alumina, assupports for sulfided nickel-tungsten hydrogenating components, fourseparate hydrocracking runs were conducted. In every instance thehydrocracking of the above-described stock was conducted at 900 F., 500psi. hydrogen partial pressure, an LHSV of 2.0 and a hydrogencirculation of 10,000 s.c.f./bbl. Prior to these hydrocracking runs thefeed stock had been hydrodenitrogenized to a nitrogen content of lessthan one part per million. When employing catalyst (l), which had 7.8percent of its pore volume in pores larger than 70 A. radius, aconversion of 70 percent to material boiling below 400 F. was obtained.When employing catalyst (2), having 11.9 percent of its pore volume inpores larger than 70 A. radius, a conversion of 67 percent to materialboiling below 400 F. was obtained. When employing catalysts (3) and (4),however, having 24.9 and 31.7 percent, respectively, of their porevolumes in pores larger than 70 A. radius, conversions to materialboiling below 400 F. of only 58 percent and 46 percent, respectively,were obtained. It will be seen, therefore, that catalysts having thepore size distribution required in the first stage of our processexhibit a marked superiority with respect to their ability to convertthe charge stock to lower boiling materials.

When a catalyst containing a sulfided hydrogenating component is to beemployed in the first stage of our process and such component is notinitially deposited in sulfided form, the catalyst can then be treatedwith a sulfiding material such as hydrogen sulfide in order to form themetal sulfides. This is carried out advantageously by treating with amixture of hydrogen and hydrogen sulfide containing up to about 20percent hydrogen sulfide, at a temperature between about 400 and 900 F.It has also been found that especially advantageous results regardingconversion are obtained when sulfiding is combined with treatment atsimilar conditions with a mixture of hydrogen and ammonia in about thesame proportions as the hydrogen sulfide. The combined pretreatment canhe carried out simultaneously or in separate steps in either order, aspreferred. This pretreating, whether conducted in single or consecutivesteps, should be at temperatures not exceeding the on-streamtemperatures to be employed in the first stage of our process and at aspace velocity of about 500 to 5,000 volumes of gas per hour per volumeof catalyst, for at least about half an hour up to several hours.

Although the first stage of our process can be conducted at atemperature anywhere in the range from about 750 to 1000 F., it ispreferred to operate at the higher temperatures within this range inorder to insure that the temperaure employed in the first stage issubstantially higher than that employed in the second stage. Thus, weprefer to conduct our first stage hydrocracking at temperatures aboveabout 800 F. Conversely We prefer to conduct the first stage of ourprocess at the lower pressures within the range from about 250 to 750p.s.i.g. Preferably, we operate the first stage of our process at thelowest pressure consistent with desired conversion thereby minimizinghydrogen consumption to the greatest extent. Thus, for example, conductof the first stage of our process at pressures in the range from about350 to about 600 p.s.i.g. is preferred. The space velocity employed inour first stage operation is also selected so as to be consistent withthe goals of obtaining desired conversion with minimum hydrogenconsumption. We prefer to employ a space velocity from about 1.0 toabout 2.0.

It should also be pointed out here that both the quantity of hydrogenconsumed, if any, and the quality of the product from the first stageboiling below 400 F. expressed in octane number is to a great extentdetermined by the particular feed stock selected for treatment. Thus,for example, the employment of a stock comprising as high as 70 to 80percent aromatic constituents can produce a product having a researchoctane rating of as much as 4, 5 or even more numbers higher than thatwhich can be obtained with a less aromatic stock. The presence of asubstantial amount of constituents containing at least one saturatedring, for example, up to about 30 percent of the total components, willnot only reduce hydrogen consumption to an extremely low level but willin many instances result in an over-all production of hydrogen in ourfirst stage operation. An illustration of such a stock is acatalytically cracked furnace oil boiling, for example, in the rangefrom about 400 to about 500 F. or 550 F. When a feed stock of thisnature is treated in the first stage of our process, the first stageproduct boiling below 400 F. usually will be about 5 to 6 leadedresearch octane numbers higher than the product obtained with similartreatment of a full range catalytically cracked furnace oil. Also theparticular operating conditions selected from the above ranges fortreatment of a particular charge stock should be such that netconversion to products boiling below 400 F. is maintained in the rangefrom about 30 to 60 percent by volume of the charge stock.

It will be found that the first stage hydrocracking operation inaccordance with our invention results in an efiluent having an unusuallyhigh aromatic content and that the fraction boiling below 400 F. willhave an eX- tremely high octane number, usually in the range of leadedresearch octane numbers higher than 95. As will be understood, theportion of the efliuent boiling above 400 P. will be comprised of asubstantial quantity of polynuclear aromatic constituents which arehighly refractory in nature. Such materials are unsuitable for recycleto the first stage of our process. Thus, in accordance with ourinvention, the 400 F.+ fraction from the first stage eflluent is passedto a second stage hydrocracking operation wherein it is contacted withhydrogen under the conditions set forth above, which conditionsfacilitate hydrocracking of the refractory polynuclear aromat cs withoutundue destruction of their cyclic nature.

The catalyst employed in this second stage operation of our inventioncan be any dual component hydrocracking catalyst comprising ahydrogenating component composited with an active cracking base. Thehydrogenating components which can be employed include Group VI and VIIImetals, and their oxides and sulfides. Thus, for example, nickel,cobalt, molybdenum, tungsten, and the oxides and sulfides thereof,either alone or in combination are satisfactory. The support for thesehydrogenating components can be any of the catalytically activerefractory metal oxides or combinations thereof, such as, for example,silica, alumina, titania, silica-alumina, silicamagnesia, etc. Thesecatalyst composites can also be promoted with from about 0.5 to 5.0percent by weight based on the total catalyst of a halogen. Particularlyadvantageous are fluorine and chlorine. Particularly suitable catalystcomposites for employment in the second stage of our process includenickel-cobalt-molybdenum or sulfided nickel-tungsten supported on asilica-alumina carrier. These components can also advantageously bepromoted with about 2 percent by weight of combined fluorine.

In this second stage hydrocracking operation of our process atemperature in the range from about 600 to about 800 F. should beemployed. It is generally preferred, however, to employ an operatingtemperature somewhat below that employed in our first stage operation,such as, for example, below about 750 F. The pres sure employed in thissecond stage operation can be in the range from about 1000 to about 3000p.s.i.g. and preferably is in the range from about 1500 to about 2500p.s.i.g. The space velocity employed in the second stage hydrocrackingof our process is generally more severe than that employed in the firststage and will usually be in the range from about 0.5 to about 2.0. Theparticular operating conditions employed should be selected from theabove ranges in order to effect a hydrogen consumption of at least 1000s.c.f.'/bbl. of 400 F.+ fraction charge and a conversion of at least percent by volume to materials boiling below 400 F.

The advantages which can be obtained by operation in accordance with theprocess of our invention can be seen from the comparison of resultsshown below.

EXAMPLE I A pretreated light fluid catalytically cracked furnace oildistillate is hydrocracked in accordance with the techniques ofconventional one-stage operation to produce a naphtha or gasolinefraction boiling in the range from C to 400 F. which has a leadedresearch octane number of about 91.5. Treatment of the same charge stockin accordance with the process of our invention results in a blendedproduct obtained by combining the C to 400 F. fraction from both thefirst and second stages of our process which has a leaded researchoctane number of about 95.5. Thus, it will be seen that the process ofour invention yields a product which is superior to that obtained byconventional techniques.

In order to dramatize the reduction in hydrogen consumption provided byour invention, a pretreated light fluid catalytically cracked furnaceoil distillate was hydrocracked under the first stage conditions of ourinvention including a temperature of 850 F., a hydrogen partial pressureof 500 psi, a space velocity of 1.0 LHSV and a hydrogenzoil ratio of10,000 s.c.f./bbl. of oil. The catalyst employed was a 6 percentnickel-19 percent tungsten on an activated alumina having 7.6 percent ofits pore volume in pores larger than 70 A. radius, prepared by dryingand calcining an aluminum hydroxide containing from 1.2 to 2.6'moles ofwater of hydration. The catalyst was pretreated at 700 F. and at 500p.s.i.g. for three hours with a gaseous mixture containing 10 percenthydrogen sulfide, 2 percent ammonia and 88 percent hydrogen. The feedstock had the following properties. I 7

Feed stock (pretreated light FCC furnace oil),

The results of this first stage operation in accordance with ourinvention are shown in Table I below.

7 Table I Yields: percent by vol. of feed C -C (percent by wt.) 2.8 C4.7 C; 5.5 C 400 F 42.0 400 F;+ 50.1 Hydrogen consumption: s.c.f./bbl.-210 Inspections of products- C 400 F. gasoline:

Gravity, API 50.0 Octane number Res., +3.0 cc. TEL 96.6 Motor, +3.0 cc.TEL 87.0 Aromatics 46.5 400 F.+:

Gravity, API 17.1 Aromatics, percent by vol 92.1 Nitrogen, p.p.m. 1Sulfur, p.p.m. Olefins, percent by vol 0.9

From the above data it will be seen that this first stage operation ofour process provided a conversion of about 50 percent by volume tomaterials boiling below 400 F. with a yield of 42 percent by volume ofhigh octane gasoline having a leaded research octane number of 96.6. Itwill be further noticed that the normally refractory, high hydrogenconsuming, aromatic feed was not only satisfactorily hydrocracked withan extremely low hydrogen consumption but that in fact suchhydrocracking was efiected with a net hydrogen production of 210standard cubic feet per barrel.

The 400 F.-+ fraction from this first stage operation and which containsmore than 90 percent by volume aromatics is charged to the second stagehydrocracking operation of our invention employing a temperaturesubstantially lower than that employed in the first stage and a pressuresubstantially higher than that employed in the first stage with anover-all consumption of hydrogen exceeding 1000 standard cubic feet perbarrel of hydrocarbon charge in order to effect a conversion greaterthan 70 percent to materials boiling below 400 F. The C to 400 F.fraction obtained from the second stage afiluent is combined with thecorresponding fraction from the first stage operation to provide ablended fraction having a leaded research octane number of 95.5. The nethydrogen consumption for the combined first and second stages of thisoperation is about 1050 standard cubic feet per barrel of light FCCfurnace oil charged to the first stage.

In order to clearly indicate the net consumption of hydrogen required toproduce a C to 400 F. fraction having a comparable octane number suchfraction from a conventional one-stage hydro-cracking operation isreformed to increase its leaded research octane number from about 91.5up to about 95.5. Combining the quantity of hydrogen consumed in theconventional hydrocracking operation and the over-all hydrogen producedin the reforming operation results in a figure of about 1750 standardcubic feet of hydrogen consumed per barrel of stock charged to thehydrocracking operation. It will be seen, therefore, that the process ofour invention provides a product comparable in quality to that obtainedin accordance with conventional techniques but with a reducedconsumption ofhydrogen in the order of 700 standard cubic feet perbarrel of charge stock.

EXAMPLE II A second example of advantages obtained through use of ourinvention is found in the hydrocracking of a full 'range pretreatedfluid 'catalytically cracked furnace oil 8 Aromatics, percent by vol51.6 ASTM distillation F;

Hydrocracking of this material in accordance with techniques ofconventional, one-stage operation produces a naphtha or gasolinefraction boiling in the range from C to 400 R, which has a leadedresearch octane number of about 88.5. Hydrocracking the same chargestock in accordance with the process of our invention results in ablended product obtained by combining the C to 400 F. fraction from bothfirst and second stage of our process which has a leaded research octanenumber of about 93.5. At the same time, hydrogen consumption forcombined first and second stages of our process is about 900 standardcubic feet perbarrel less than for the conventional hydrocrackingprocess. Thus, it can be seen that our invention not only yields asuperior product but does so at a significantly lower hydrogenconsumption.

EXAMPLE III To demonstrate further the superior results obtained in thepractice of our invention over those obtainable with a two-stage processin which dehydrogenative conditions are employed in the first stagealong with a conventional alumina base hydrocracking catalyst acomparison of the following results can be made. Two separate two-stagehydrocracking processes are operated employing substantially the sameoperating conditions in the first stages as well as in the second stagesof both processes. In the first process a conventional alumina basehydrocracking catalyst is employed in the first stage while the secondprocess is conducted in accordance with our invention employing thespecific catalyst required in the first stage of our process. Theeflluent from the first stage of the process employing the conventionalalumina base catalyst comprises about 32 percent by volume of C to 400F. gasoline having a leaded research octane number of about 90 to 95. Onthe other hand, the affluent from the first stage hydrocrackingoperation in accordance with our invention comprises about 40 percent byvolume of a C to 400 F. gasoline having a leaded research octane numberabove about 96. The 400 F.+ fraction from the first stages of bothprocesses are then subjected to conventional hydrocracking in a secondstage employing a conventional silicaalumina base hydrocrackingcatalyst. The C to 400 F.

fraction from the second stage of each of the two processes is thenblended with the cor-responding fraction from the first stage of therespective process. The leaded research octane number of the blendobtained from the first process employing a conventional alumina basecatalyst in the first stage is still somewhat lower than the leadedresearch octane number of about which is obtained in accordance with theprocess of our invention. Although the hydrogen consumption rate of thetwo-stage process employing a conventional alumina base catalyst in thefirst stage is substantially lower than the 1750 standard cubic feet perbarrel shown above for a conventional one-stage hydrocracking operation,the hydrogen consumption rate is still some 50 to standard cubic feetper barrel greater than the hydrogen consumption rate of 1050 standardfeet per barrel obtained in the two-stage process of our invention.Thus, it can again be seen that the process of our invention generallyprovides a product of superior quality at a reduced rate of hydrogenconsumption over that obtained by more conventional practice having agreater hydrogen consumption.

In addition to the advantages obtained in accordance with our inventionand pointed out above, the practice of our inventive process requiringthe employment of a particular type of alumina in the first stageeliminates the necessity of employing a conventional silica-alumina basehydrocracking catalyst in such first stage. The absence of asilica-alumina base catalyst permits conduct of the desired first stagereactions for an extended period of time and prevents an excessivelyhigh degree of cracking which in turn deleteriously effects catalystlife.

We claim:

1. A two-stage hydrocracking process which comprises hydrocracking in afirst stage a hydrocarbon stock boiling in the range from about 400 toabout 850 F., containing less than about ppm. nitrogen, containing up toabout 80 percent by volume of aromatic hydrocarbons and containing atleast 30 percent by volume of hydrocarbons having at least one saturatedring by contacting the hydrocarbon stock with hydrogen at a temperaturein the range from about 800 to about 1000 F., a pressure in the rangefrom about 350 to about 650 p.s.i.g., a space velocity in the range fromabout 1.0 to about 2.0 volumes of hydrocarbon stock per hour per volumeof catalyst, with a hydrogen consumption of less than 200 standard cubicfeet of hydrogen per barrel of hydrocarbon stock while in the presenceof a catalyst comprising a hydrogenation component consistingessentially of sulfided nickel-tungsten wherein the tungsten comprisesfrom about 3 to about 25 percent by weight of the total catalyst and thenickel comprises from about 0.5 to about percent by weight of the totalcatalyst, composited with an activated alumina having less than about 10percent of its pore volume in pores having a radius greater than 70 A.,thereby effecting a conversion from about 30 to about 60 percent byvolume to materials boiling below the initial boiling point of thehydrocarbon charge stock, separating from the eflluent of the firststage a gasoline fraction boiling up to 400 F. and a fraction boilingabove 400 F., hydrocracking the fraction boiling above 400 F. in asecond stage by contacting said 400 F.+ fraction with hydrogen at atemperature in the range from about 600 to about 750 F., a pressure inthe range from about 1500 to about 2500 p.s.i.g., a space velocity inthe range from about 0.5 to about 2.0 volumes of 400 F.+ fraction perhour per volume of catalyst, with a hydrogen consumption of at least1,000 standard cubic feet of hydrogen per barrel of 400 F.+ fractionwhile in the presence of a dual component hydrocracking catalystconsisting essentially of a hydrogenation component selected from thegroup consisting of Group VI and VIII metals, their oxides and sulfides,supported on a refractory metal oxide carrier having substantialcracking activity, thereby eITecting a conversion of a least percent byvolume to materials boiling below 400 F. and separating from theefiluent from the second stage a second gasoline fraction boiling up to400 F.

2. The process of claim 1 wherein the catalysts contain from about 0.5to about 5.0 percent by weight of a halogen.

3. The process of claim 1 wherein there is a net production of hydrogenin the first stage thereof.

References Cited UNITED STATES PATENTS 5/1965 Kozlowski et al 2081115/1965 Flinn et a1 208-112 UNITED STATES PATENT OFFICE CERTIFICATE OFCORRECTION Patent No. 3,360,456 December 26, 1967 Joseph K. Kosiba etal.

pears in the above numbered pat- It is hereby certified that error ap ntshould read as ent requiring correction and that the said Letters Patecorrected below.

Column 1, line 38, for "difficulty" read difficultly column 7, line 44,for "affluent" read effluent column 8, line 3, for "545" read 454 line41, for "affluent" read effluent Signed and sealed this 21st day ofJanuary 1969.

(SEAL) Attest:

EDWARD J. BRENNER Commissioner of Patents Edward M. Fletcher, Jr.

Attesting Officer

1. A TWO-STAGE HYDROCRACKING PROCESS WHICH COMPRISES HYDROCRACKING IN AFIRST STAGE A HYDROCARBON STOCK BOILING IN THE RANGE FROM ABOUT 400* TOABOUT 850*F., CONTAINING LESS THAN ABOUT 5 P.P.M. NITROGN, CONTAINING UPTO ABOUT 80 PERCENT BY VOLUME OF AROMATIC HYDROCARBONS AND CONTAINING ATLEAST 30 PERCENT BY VOLUME OF HYDROCARBONS HAVING AT LEAST ONE SATURATEDRING BY CONTACTING THE HYDROCARBON STOCK WITH HYDROGEN AT A TEMPERATUREIN THE RANGE FROM ABOUT 800* TO ABOUT 1000*F., A PRESSURE IN THE RANGEFROM ABOUT 350 TO ABOUT 650 P.S.I.G., A SPACE VELOCITY IN THE RANGE FROMABOUT 1.0 TO ABOUT 2.0 VOLUMES OF HYDROCARBON STOCK PER HOUR PER VOLUMEOF CATALYST, WITH A HYDROGEN CONSUMPTION OF LESS THAN 200 STANDARD CUBICFEET OF HYROGEN PER BARREL OF HYDROCARBON STOCK WHILE IN THE PRESENCE OFA CATALYST COMPRISING A HYDROGENATION COMPONENT CONSISTING ESSENTIALLYOF SULFIDED NICKEL-TUNGSTEN WHEREIN THE TUNGSTEN COMPRISES FROM ABOUT 3TO ABOUT 25 PERCENT BY WEIGHT OF THE TOTAL CATALYST AND THE NICKELCOMPRISES FROM ABOUT 0.5 TO ABOUT 10 PERCENT BY WEIGHT OF THE TOTALCATALYST, COMPOSITED WITH AN ACTIVATED ALUMINA HAVING LESS THAN ABOUT 10PERCENT OF ITS PORE VOLUME IN PORES HAVING A RADIUS GREATER THAN 70 A.,THEREBY EFFECTING A CONVERSION FROM ABOUT 30 TO ABOUT 60 PERCENT BYVOLUME TO MATERIALS BOILING BELOW THE INITIAL BOILING POINT OF THEHYDROCARBON CHARGE STOCK, SEPARATING FROM THE EFFLUENT OF THE FIRSTSTAGE A GASOLINE FRACTION BOILING UP TO 400*F. AND A FRACTION BOILINGABOVE 400*F., HYDROCRACKING THE FRACTION BOILING ABOVE 400*F. IN ASECOND STAGE BY CONTACTING SAID 400*F.+ FRACTION WITH HYDROGEN AT ATEMPERATURE IN THE RANGE FROM ABOUT 600* TO ABOUT 750*F., A PRESSURE INTHE RANGE FROM ABOUT 1500 TO ABOUT 2500 P.S.I.G., A SPACE VELOCITY INTHE RANGE FROM ABOUT 0.5 TO ABOUT 2.0 VOLUMES OF 400*F.+ FRACTION PERHOUR PER VOLUME OF CATALYST, WITH A HYDROGEN CONSUMPTION OF AT LEAST1,000 STANDARD CUBIC FEET OF HYDROGEN PER BARREL OF 400*F.+ FRACTIONWHILE IN THE PRESENCE OF A DUAL COMPONENT HYDROCRACKING CATALYSTCONSISTING ESSENTIALLY OF A HYDROGENATION COMPONENT SELECTED FROM THEGROUP CONSISTING OF GROUP VI AND VIII METALS, THEIR OXIDES AND SULFIDES,SUPPORTED ON A REFRACTORY METAL OXIDE CARRIER HAVING SUBSTANTIALCRACKING ACTIVITY, THEREBY EFFECTING A CONVERSION OF AT LEAST 70 PERCENTBY VOLUME TO MATERIALS BOILING BELOW 400*F. AND SEPARATING FROM THEEFFLUENT FROM THE SECOND STAGE A SECOND GASOLINE FRACTION BOILING UP TO400*F.